Semiconductor packages can be found in practically every electronic product manufactured today. As manufacturers strive to decrease the size while expanding the functionality of such products, the need for greater semiconductor package density increases. Multi-chip modules have been developed to help meet this need. Multi-chip modules generally have a number of integrated circuit (IC) chips, commonly referred to as dies, and other semiconductor components within a single semiconductor package. The dies and other semiconductor components can be arranged in various manners, such as vertically, horizontally, or in various combinations.
One multi-chip module approach is to stack a die on top of another and enclose the stacked dies in a single semiconductor package. Stacked die semiconductor packages are much smaller than if the dies were each packaged separately. Such stacked die packages also offer a number of manufacturing advantages. For example, stacked dies are easier to handle and assemble, and generally are fabricated faster and cheaper than multiple semiconductor packages each having a single die.
In some stacked die semiconductor packages, an interposer may be used. For example, U.S. Pat. No. 6,861,288 to Shim et al. describes, as illustrated in FIG. 1, a method of fabricating a stacked semiconductor package 100 that includes mounting a first semiconductor device 102 on a substrate 104, supporting an interposer 106 electrically connected to the substrate 104 above the first semiconductor device 102 opposite the substrate 104, and mounting a second semiconductor device 108 on the interposer 106. See col. 3, lines 48-54. In this arrangement, a thermal glue or film adhesive spacer 110 is attached to the interposer 106. See col. 5, lines 58-62. The interposer 106 may be supported and reinforced by a thermally conductive metal stiffener 112. See col. 6, lines 1-5. Also, the side and top perimeter of the interposer 106 are encapsulated but the top central portion of the interposer 106 is not encapsulated thereby forming a partially molded bottom package having an open cavity on top in which the central part of the top of the interposer 106 is exposed. See col. 6, lines 13-19.
A high density multi-chip interconnect (HDMI) decal may be used in some stacked die semiconductor packages. For example, U.S. Pat. No. 5,905,639 to Warren describes, as illustrated in FIG. 2, a three-dimensional circuit structure 200. The circuit structure 200 interconnects an integrated circuit chip 202 and additional active devices and passive components 204-212 to a substrate 214 using an HDMI decal 216 disposed on the integrated circuit chip 202. See col. 1, lines 28-33. In this arrangement, the active and passive components 204-212 are connected to the HDMI decal 216 using conductive or non-conductive epoxy. See col. 1, lines 50-53.
Despite the advantages of the various developments in semiconductor packaging technology, there remains a need for increased semiconductor package density.